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1.
Resistance to bacterial wilt, caused by Ralstonia solanacearum , in tomato lines CRA 66 and Caraïbo is reported to be decreased by root-knot nematode galling and by introduction of the Mi gene for nematode resistance. The Mi gene is located on tomato chromosome 6, which also carries a major quantitative trait locus (QTL) for resistance to bacterial wilt. Bacterial wilt resistance was evaluated in F3-progenies derived from two crosses between near-isogenic lines, Caraïbo × Carmido and CRA 66 × Cranita, differing for small and large introgressions from Lycopersicon peruvianum that carry the Mi gene, respectively. These introgressed regions were mapped using RFLP markers. Plants homozygous Mi+/Mi+ (susceptible to the nematode) and homozygous Mi/Mi (resistant) for the Mi gene were selected in F2 and used to produce F3 progenies. Parents and F3-lines with Mi/Mi had resistance to bacterial wilt reduced by 30% in Caraïbo × Carmido and by 15% in CRA 66 × Cranita. Caraïbo and Carmido were demonstrated to be isolines and the small introgression from L. peruvianum resulted in loss of the QTL for bacterial wilt resistance, which is probably allelic or linked in repulsion to the Mi gene. In contrast, resistance to bacterial wilt segregated in the F3 lines from the cross CRA 66 × Cranita, giving families varying in resistance between the levels shown by the parents. Consequently, two hypotheses were considered: (i) after only four backcrosses, the parents were not isolines and the genes for resistance to bacterial wilt from CRA 66 were still segregating, and (ii) the parents were isolines and variation in resistance to bacterial wilt in F3 was due to recombination events among the large L. peruvianum introgressed chromosome region from Cranita.  相似文献   

2.
番茄细菌性斑点病菌无毒基因研究进展   总被引：1，自引：0，他引：1  
番茄细菌性斑点病是影响番茄产量和品质的重要病害,Pseudomonas syringaepv.tomato(Pst)为其病原菌,其与番茄的互作系统是研究植物抗感病机理的典型模式系统。Pst存在2种无毒基因:avrPto和avrPtoB,它们编码的蛋白质均能与番茄抗性基因Pto编码的Ser-Thr蛋白激酶互作,符合Flor"基因对基因"学说。AvrPto和AvrPtoB在表达Pto的抗性植物中,与Pto互作,表现无毒功能,引发植物防御反应;而在缺失Pto的感病植物中,它们具有毒性,促进细菌的生长。本文综述了番茄细菌性斑点病菌无毒基因avrPto及avrPtoB的结构特点及其功能,这有助于了解病原物与植物的互作机制,对认识植物的感病性、抗病性以及植物防御反应都具有重要意义。  相似文献   

3.
The tomato line IRB-301-31, resistant to fusarium crown and root rot ( Fusarium oxysporum f.sp. radicis-lycopersici ) was crossed with two susceptible cultivars, Motelle and Earlypak No. 7. When F1, F2 and backcross progenies were inoculated at the one-leaf stage with a suspension of spores of the pathogen, all could be classified as either resistant (healthy) or susceptible (dead). The ratios of resistant to susceptible plants indicated that resistance was conferred by a single dominant gene, designated Fr1.  相似文献   

4.
The reactions of several tomato cultivars and the genetic basis of resistance to an isolate of Alternaria alternata f. sp. lycopersici were examined. Among the 105 cultivars tested only two, Regal and Toper, were susceptible, while the remainder were highly resistant. The resistant cultivar ACE 55 VF (P;) was crossed with the susceptible cultivar Earlypak No. 7 (P1)- When F1, F2, F3, BC1, BC1 selfed, F2 X P2 and BC1P2 x P1 progenies were inoculated at the two-leaf stage with a suspension of spores of the pathogen, the ratios of resistant to susceptible plants indicated that resistance was conferred by a single dominant gene.  相似文献   

5.
我国地方品种是小麦白粉病抗性的重要来源之一,为了对地方品种抗源的利用奠定基础,采用常规杂交方法,以感病品种Chancellor分别与我国小麦抗病地方品种蚂蚱麦、小白冬麦、游白兰、红卷芒进行正交和反交,获得F1、F2代。根据白粉菌菌株的毒谱选用E09菌株对Chancellor与小白冬麦、游白兰、红卷芒的杂交后代进行苗期抗性鉴定和统计分析,选用E30菌株对Chancellor与蚂蚱麦的杂交后代进行苗期抗性鉴定和统计分析。结果表明4个品种在正、反交情况下均表现出由一对隐性基因控制的抗性,说明这4个地方品种属于核遗传,其抗性是由一对隐性基因控制的。  相似文献   

6.
根据已报道的番茄抗细菌性斑点病基因Pto家族成员之一LescPtoF的序列特征设计一对引物,通过PCR扩增,从我国10个抗病栽培番茄品种和3个感病品种获得13个同源序列。Blast结果表明,2个来自抗病品种和2个来自感病品种的核苷酸序列均和报道的LescPtoF完全一致。其余9个核苷酸序列和LescPtoF序列相似性最低为91%,它们之间相似性最低为87%。具有完整读码框的11个核苷酸序列所编码氨基酸与LescPtoF蛋白相似性最低为84%,11个氨基酸序列之间相似性最低也为84%。研究结果表明我国栽培番茄品种LescPtoF基因同源序列的分布具有多态性。  相似文献   

7.
番茄黄萎病抗病基因Ve的AFLP和SSR分子标记   总被引：1，自引：0，他引：1  
 本研究以番茄抗病品种05046与感病品种051355配制杂交组合,接种鉴定F1代及F2代分离群体的黄萎病发生情况,结果表明,番茄黄萎病属单基因显性遗传。用545对AFLP引物和101对SSR引物对两个亲本、抗感池及F2代分离群体进行AFLP和SSR分析,得到3个与番茄抗黄萎病基因Ve连锁的AFLP标记和1个SSR标记,分别是E66M84-A、E78M84-D、E66M40-A和SSR599,与抗病基因Ve的连锁遗传距离分别为10.3、14.2、30.5 和12.5 cM。  相似文献   

8.
Newcombe G  Ostry M 《Phytopathology》2001,91(11):1081-1084
ABSTRACT Stem canker, caused by Septoria musiva, is the most serious disease limiting intensive hybrid poplar culture in eastern North America. Populus deltoides (D) is itself resistant, but the susceptibility of western black cottonwood, P. trichocarpa (T) is apparently dominant in the F(1) generation. To test a hypothesis of recessive inheritance of canker resistance, a three-generation T x D pedigree was deployed in the field in Iowa and Minnesota. In both sites and in keeping with expectations, P. trichocarpa and its F(1) hybrids were susceptible to canker, whereas the P. deltoides parent was resistant. In Iowa, 10 of 70 F(2) (TD x TD) individuals were free of canker, suggesting that a single recessive gene might control resistance. In the third year in Minnesota, more resistant individuals than expected were seen in the F(2) generation and in TD x D and T x TD backcross progenies due to disease escape. By the fifth year, this was no longer an issue, but winter injury may have eliminated many clones. Qualitatively, however, evidence for recessive inheritance of resistance was still obtained. The only canker-free clones were in the TD x D backcross and the F(2) generation, the two progenies in which they were expected. However, conclusive evidence that recessive canker resistance is conferred by a single gene was not obtained in this field study.  相似文献   

9.
ABSTRACT The inheritance of resistance to Leptosphaeria maculans, the causal agent of black leg of crucifers, was studied in Brassica juncea. Three resistant accessions (UM3021, UM3043, and UM3323) and one susceptible accession (UM3132) of B. juncea were crossed in a complete diallel. Parents, F(1), and F(2) progenies were evaluated for all crosses using both cotyledon and stem inoculation. Cotyledon reaction was evaluated with two isolates of L. maculans, but stem reaction was evaluated with one isolate. Disease reactions observed for individual plants were the same for both inoculation methods and for both isolates of the pathogen for cotyledon reaction. No segregation was observed for the crosses between resistant accessions (UM3043 x UM3323 and UM3021 x UM3323), but a few susceptible plants were observed in the F(2) progeny of crosses between resistant parents (UM3021 x UM3043). This was probably due to heterozygosity in some parental plants of UM3021. For crosses be tween the susceptible parent and resistant parents, F(1) plants for two crosses were all resistant. For cross UM3132 x UM3021, some susceptible plants occurred, which was also suggestive of heterozygosity in UM3021. Although resistance in F(1) was dominant, for F(2) populations, segregation fit either 13:3, 3:1, or 1:3 ratios, indicating that resistance can be either adominant or recessive trait. F(3) families derived from some susceptible F(2) plants from crosses UM3021 x UM3132 and UM3043 x UM3132 were evaluated using the cotyledon inoculation method only. Segregation of F(2) plants and F(3) families in crosses involving resistant and susceptible parents indicated that the resistance to L. maculans in B. juncea is controlled by two nuclear genes with dominant recessive epistatic gene action.  相似文献   

10.
Transgenic tomato plants containing the coat protein (CP) gene of Cucumber mosaic virus (CMV) of subgroup IB were developed through Agrobacterium-mediated transformations. The progenies of transgenic plants showed the presence of transgene, its expression and translation of 26 KDa CP. The T1 and T2 generation plants were evaluated for resistance against challenge inoculations by a homologous strain of CMV. Visual observations of challenged transgenic plants categorized them into resistant, tolerant and susceptible as compared with untransformed control plants. Out of 33 plants of the T1 generation, 36.3% showed resistance and remained symptomless throughout their life, 48.4% showed tolerance which developed delayed symptoms of mild mosaic, and 15.1% showed susceptibility to CMV which developed severe systemic mosaic and leaf distortion symptoms after 30?days of virus challenge. Out of 120 plants of the T2 generation, 60% showed resistance, 26.6% were tolerant and only 13.3% were found susceptible to challenge inoculations of CMV. Resistant transgenic plants also showed less CP accumulation in systemic upper leaves as compared with challenged untransformed plants. In this study, CP of a CMV subgroup IB strain has demonstrated a significant level of resistance in transgenic tomato plants against the CMV strain. The strategy may be applied for better quality and productivity of tomato crops.  相似文献   

11.
Bacterial spot caused by several Xanthomonas spp. is an economically important disease of tomato (Solanum lycopersicum L.). Host resistance to the disease is partially dominant or incomplete, which requires accurate assessment of disease severity for genetic studies of resistance. In the present study, three independent experiments were conducted to investigate the feasibility of using image analysis to estimate foliar disease severity of bacterial spot in tomato. The resistant line PI 114490 and the susceptible line OH 88119 were used in the first experiment, five tomato lines (PI 114490, PI 128216, Hawaii 7981, Hawaii 7998, and Fla. 7600) with a range of resistance and OH 88119 were used in the second experiment, and 439 F2 individuals from a cross between OH 88119 and PI 114490 were used in the third experiment. Tomato plants were spray-inoculated with bacterial spot race T3. Five diseased leaves from each plant were randomly collected and scanned to obtain digital images 21 days after inoculation. The disease severity (% leaf area) was measured using image analysis. The susceptible line OH 88119 showed the most severe disease. The resistant line PI 114490 showed the least severe disease, and was not significantly different to PI 128216 or Hawaii 7981. These results indicated that image analysis could be used to distinguish tomato lines with different resistance to bacterial spot. Marker-trait association analysis identified four quantitative trait loci conferring resistance to race T3 in PI 114490 using data obtained from image analysis, the Horsfall-Barratt (HB) category scale data, and HB midpoint converted values. However, the disease severity was slightly underestimated using the HB category scale and the phenotypic variation explained by each marker was overestimated using the HB category data compared to using the image analysis-measured disease severity data. Therefore, image analysis could provide a consistent, accurate and reliable method compared to the HB scale to estimate disease severity for genetic studies of foliar bacterial spot in tomato.  相似文献   

12.
Random amplified polymorphism DNA (RAPD) and bulk segregant analysis (BSA) approaches were used to characterize the molecular marker linked to the Phytophthora infestans resistance gene Ph-3 in tomato. A total of 800 RAPD primers were screened. One RAPD marker UBC#602 was identified to be tightly linked to the Ph-3 gene. The marker was successfully converted into a co-dominant sequence characterized amplified region (SCAR) marker. The SCAR marker SCU602 was used to analyze 96 F2 progenies and fitted the expected 1:2:1 Mendelian segregation ratio. Forty one tomato inbred lines were screened using the SCAR marker in comparison with a reference marker linked to the Ph-3 gene and both markers gave the same results. SCU602 was further validated for association to resistance and its potential in MAS in 72 tomato lines and cultivars. The marker identified three genotypes harbouring the resistance allele. This SCAR marker can be used in breeding programs for the selection of the Ph-3 gene for Phytophthora infestans resistance.  相似文献   

13.
Bacterial spot of tomato (Solanum lycopersicum) is caused by four species of Xanthomonas. The disease causes significant yield losses and a reduction in fruit quality. Physiological races have been described with tomato race 3 (T3) corresponding to strains of Xanthomonas perforans. The breeding line Hawaii 7981 (hereafter H7981) shows a hypersensitive reaction (HR) to race T3 strains conditioned by the interaction of the host resistance locus Xv3 and the bacterial effector avrXv3. The Xv3 gene is required for H7981-derived resistance to be effective under field conditions, though its expression is subject to genetic background. The segregation of HR in F(2) populations derived from H7981 crossed to processing tomato parents OH88119 and OH7870 was studied in 331 progeny, with the two independent crosses providing validation. We screened 453 simple-sequence repeat, insertion/deletion, and single-nucleotide polymorphism markers and identified 44 polymorphic markers each for the OH88119 and OH7870 populations covering 84.6 and 73.3% of the genome, respectively, within 20 centimorgans (cM). Marker-trait analysis using all polymorphic markers demonstrated that Xv3-mediated resistance maps to chromosome 11 in the two independent crosses. Allelism tests were conducted in crosses between lines carrying Xv3 derived from H7981, Rx-4 derived from plant introduction (PI) 128216, and resistance derived from PI 126932. These allelism tests suggested that the loci conditioning HR to race T3 strains are linked within 0.1 cM, are allelic, or are the same gene.  相似文献   

14.
苜蓿抗褐斑病基因ISSR标记的筛选及验证   总被引：4，自引：0，他引：4  
运用ISSR分子标记技术和BSA法,对四倍体紫花苜蓿(Medicago sativaL.)F1代进行抗褐斑病基因连锁的分子标记筛选。结果表明,在93个随机引物中,有32个引物能够产生清晰稳定的扩增条带,其中6个引物在中抗杂交F1代、高抗、高感各12单株所组成的抗、感DNA池间出现差异性条带。随后,对此6个标记进行单株检验,结合均值差检验法,结果显示20-R750与苜蓿褐斑病的抗病基因紧密连锁,11-S750与苜蓿褐斑病感病的基因紧密连锁,研究结果为紫花苜蓿抗褐斑病的鉴定和分子标记辅助抗病育种提供了依据。  相似文献   

15.
根据已报道的番茄Pto基因家族成员之一LescPtoF基因的序列特征设计引物,通过PCR扩增从3个感病番茄品种中获得3个同源序列。Blast结果表明其中两个序列和报道基因完全一致,另外一个和报道基因的序列相似性为99%,表明感病番茄品种中也存有LescPtoF基因的同源序列。  相似文献   

16.
Shi AN  Leath S  Murphy JP 《Phytopathology》1998,88(2):144-147
ABSTRACT A major gene for resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici = Erysiphe graminis f. sp. tritici) has been successfully transferred into hexaploid common wheat (Triticum aestivum, 2n = 6x = 42, AABBDD) from wild einkorn wheat (Triticum monococcum subsp. aegilopoides, 2n = 2x = 14, AA). NC96BGTA5 is a germ plasm line with the pedigree Saluda x 3/PI427662. The response patterns for powdery mildew resistance in NC96BGTA5 were tested with 30 differential isolates of B. graminis f. sp. tritici, and the line was resistant to all tested isolates. The analyses of P(1), P(2), F(1), F(2), and BC(1)F(1) populations derived from NC96BGTA5 revealed two genes for wheat powdery mildew resistance in the NC96BGTA5 line. One gene, Pm3a, was from its recurrent parent Saluda, and the second was a new gene introgressed from wild einkorn wheat. The gene was determined to be different from Pm1 to Pm21 by gene-for-gene and pedigree analyses. The new gene was identified as linked to the Pm3a gene based on the F(2) and BC(1)F(1) populations derived from a cross between NC96BGTA5 and a susceptible cultivar NK-Coker 68-15, and the data indicated that the gene was located on chromosome 1A. It is proposed that this new gene be designated Pm25 for wheat powdery mildew resistance in NC96BGTA5. Three random amplified polymorphic DNA markers, OPX06(1050), OPAG04(950), and OPAI14(600), were found to be linked to this new gene.  相似文献   

17.
Gunduz I  Buss GR  Chen P  Tolin SA 《Phytopathology》2004,94(7):687-692
ABSTRACT Resistance to Soybean mosaic virus (SMV) was identified in PI 88788 soybean, a germ plasm accession from China that is used widely as a source of resistance to soybean cyst nematode. Strains SMV-G1 through -G7 infected the inoculated leaves of PI 88788 but were not detected in upper, noninoculated trifoliolate leaves. Inheritance of resistance was determined by inoculating progenies of crosses of PI 88788 with susceptible cvs. Essex and Lee 68 with SMV strains G1 and G7. Allelomorphic relationships with known genes for resistance to SMV were tested in crosses with the resistant genotypes PI 96983, L29, and V94-5152, possessing Rsv1, Rsv3, and Rsv4 genes, respectively. Data analyses showed that resistance in PI 88788 to SMV-G1 is controlled by a single, partially dominant gene; however, to SMV-G7, the same gene was completely dominant. The PI 88788 gene was independent of the Rsv1 and Rsv3 loci, but allelic to Rsv4 in V94-5152. Expression of the Rsv4 gene in PI 88788 resulted in a reduced number of infection sites and restricted short- and long-distance movement of virus, rather than hypersensitivity. A unique late susceptible phenotype was strongly associated with heterozygosity. This gene has potential value for use in gene pyramiding to achieve resistance to several SMV strains, as well as for rate-reducing resistance.  相似文献   

18.
ABSTRACT Spot blotch, caused by Cochliobolus sativus, is one of the most common foliar diseases of barley in the upper midwest region of the United States. To examine the genetics of host-specific virulence in C. sativus, a cross was made between isolate ND90Pr (which exhibits high virulence on barley genotype Bowman and low virulence on genotype ND 5883) and ND93-1 (which exhibits low virulence on both genotypes). Ascospore progeny segregated 48:55 for low virulence/high virulence on Bowman, indicating the presence of a single virulence gene in isolate ND90Pr. To complement the study of host-specific virulence in the pathogen, an experiment also was conducted on the genetics of specific resistance in the host. Progeny from a Bowman/ND 5883 cross were evaluated for their infection responses (IRs) to isolate ND90Pr at the seedling stage. The F(2) population segregated 1:3 for low IRs (resistant)/high IRs (susceptible), indicating the presence of a single resistance gene in genotype ND 5883. This result was confirmed in the F(3) generation, as a 1:2:1 ratio was found for homozygous resistant, segregating, and homozygous susceptible families, respectively. The data from this study demonstrate that both virulence in the pathogen and resistance in the host are under monogenic control in this specific host genotype/fungal isolate combination.  相似文献   

19.
Frankliniella schultzei Trybon (Thysanoptera: Thripidae) is an important pest of tomato plants. The need for more healthful foods is stimulating the development of techniques to increase plant resistance to phytophagous insects. The objective of this research was to evaluate the effect of calcium silicate and an organic mineral fertilizer, alone or in combination, on the resistance of tomato plants to F. schultzei. The treatments consisted of: control (T1), calcium silicate (T2), organic mineral fertilizer (T3), and calcium silicate with organic mineral fertilizer (T4). The mortality of nymphs of this thrips and the number of lesions on tomato leaves were evaluated after three, six, nine and 12 applications of these products. The number of F. schultzei individuals and of lesions on tomato leaves was lower in treatments T2 and T4 than in T1 and T3, showing a possible increase in tomato resistance to this pest. The increase in the number of applications of calcium silicate and the organic mineral fertilizer increased the mortality of nymphs and reduced the damage by this insect on tomato leaves, mainly after nine applications.  相似文献   

20.
ABSTRACT Stripe rust is one of the most important diseases of wheat and barley worldwide. On wheat it is caused by Puccinia striiformis f. sp. tritici and on barley by P. striiformis f. sp. hordei Most wheat genotypes are resistant to P. striiformis f. sp. hordei and most barley genotypes are resistant to P. striiformis f. sp. tritici. To determine the genetics of resistance in wheat to P. striiformis f. sp. hordei, crosses were made between wheat genotypes Lemhi (resistant to P. striiformis f. sp. hordei) and PI 478214 (susceptible to P. striiformis f. sp. hordei). The greenhouse seedling test of 150 F(2) progeny from the Lemhi x PI 478214 cross, inoculated with race PSH-14 of P. striiformis f. sp. hordei, indicated that Lemhi has a dominant resistance gene. The single dominant gene was confirmed by testing seedlings of the F(1), BC(1) to the two parents, and 150 F(3) lines from the F(2) plants with the same race. The tests of the F(1), BC(1), and F(3) progeny with race PSH-48 of P. striiformis f. sp. hordei and PST-21 of P. striiformis f. sp. tritici also showed a dominant gene for resistance to these races. Cosegregation analyses of the F(3) data from the tests with the two races of P. striiformis f. sp. hordei and one race of P. striiformis f. sp. tritici suggested that the same gene conferred the resistance to both races of P. striiformis f. sp. hordei, and this gene was different but closely linked to Yr21, a previously reported gene in Lemhi conferring resistance to race PST-21 of P. striiformis f. sp. tritici. A linkage group consisting of 11 resistance gene analog polymorphism (RGAP) markers was established for the genes. The gene was confirmed to be on chromosome 1B by amplification of a set of nullitetrasomic Chinese Spring lines with an RGAP marker linked in repulsion with the resistance allele. The genetic information obtained from this study is useful in understanding interactions between inappropriate hosts and pathogens. The gene identified in Lemhi for resistance to P. striiformis f. sp. hordei should provide resistance to barley stripe rust when introgressed into barley cultivars.  相似文献   

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